|
Routines |
| Prev: 39123 | Up: Map | Next: 39204 |
|
Used by the routines at UpdateFoamEntity and UpdateSaucerEntity.
Turns an entity by a step towards the heading in field 32 by changing bits 1-5 of the current heading in field 17.
|
||||||||||
| TurnEntity | 39180 | LD A,(IX+17) | Fetch the current heading of the entity. | |||||||
| 39183 | AND %00111110 | Use bits 1-5. | ||||||||
| 39185 | LD L,A | Copy it into L. | ||||||||
| 39186 | SUB (IX+32) | Subtract the wanted heading of the entity. | ||||||||
| 39189 | RET Z | Return if the entity is already heading that way. | ||||||||
| 39190 | BIT 5,A | Test bit 5 of the difference. | ||||||||
| 39192 | LD A,B | Fetch the size of the step. | ||||||||
| 39193 | JR NZ,TurnEntity_Apply | Jump to TurnEntity_Apply if the step is to be added. | ||||||||
| 39195 | NEG | Negate the step. | ||||||||
| TurnEntity_Apply | 39197 | ADD A,L | Add the step to the current heading. | |||||||
| 39198 | AND %00111110 | Use bits 1-5. | ||||||||
| 39200 | LD (IX+17),A | Store the new heading of the entity. | ||||||||
| 39203 | RET | Return. | ||||||||
| Prev: 39123 | Up: Map | Next: 39204 |